This invention relates to automatic door closing devices, and, in particular, to pivot hinges with automatic door closing mechanism.
A pivot hinge supporting the top end of a door and having an automatic door closing mechanism is well known in the prior art, as disclosed in, for example, British Pat. No. 1,227,324. However, when door closing function is not desired, it is required to exchange the pivot hinge having a door closing mechanism by a pivot hinge without door closing mechanism. On the other hand, when a door closing function is desired on a door in which a pivot hinge is used, it is required to exchange the pivot hinge with another pivot hinge having a door closing mechanism. Such an exchanging operation is complicated.
In order to simplify this operation, a pivot hinge to which a door closing device can be readily attached and removed without exchanging hinges was proposed in U.K. patent Application No. GB 2033468 A. However, the hinge disclosed in this patent application is for supporting the bottom end of the door, and cannot be used for supporting the top end of the door, because the door closing device is prone to fall down or out after long use. Also, in a pivot hinge with door closing device which utilized an oil damper, oil commonly leaks downward therefrom on to the door.